so what i do is i bring down the tax rates. >> governor romney's proposal calls for a $5 trillion tax cut. the average middle class family with children would pay about $2,000 more. it is not possible to come up with enough deductions and loopholes that only affect individuals to avoid either raising the deficit or burdening the middle class. it's math. >> reporter: on medicare and social security,one agreement. >> neither the president nor are are i are proposing any changes. >> aarp has said that your plan would weaken medicare, substantially. >> romney fired back a a major debate moment that the president weakened the economy by his focus on health care. >> i don't know how the president could have come into office facing rising unploimt and spending energy and passion fighting for obama care. >> we did work on this alongside working on jobs. this is part of making sure that middle class families are secure in this country. >> a substantial debate. no zingers. i'm steve handles, nbc news, denver. >> as mentioned, we heard a t lo of promises from both candidates. did any resonate wi